In order to prevent growth of mildew on various products, fixtures and the like, there have been employed addition of mildew proofing agents such as those disclosed in H. Horiguchi, "Bokin Bobai no Kagaku " published by Sankyo Shuppan (1982), or coating treatment with paints containing mildew proofing agents. From an ideal viewpoint a mildew proofing agent should have such properties that it is harmless to man and beast and very efficacious on mildew and is readily dissolved or dispersed in a product, but it is slightly soluble in water and nonvolatile. However, such a mildew proofing agent is not yet actually obtained and, usually, efficacy of a mildew proofing agent is lost due to agglomeration in a product, migration and the like. On the other hand, in Journal of Coatings Technology, 50, [636] 49; [639] 62 (1978), there is proposed a mildew resistant polymer obtained by using a monomer to which a mildew proofing agent is chemically attached to a monomer. However, its efficacy as a mildew proofing agent is still insufficient.
On the other hand, synthetic elastomers such as polyurethane elastomer have excellent wear resistance, oil resistance, freeze resistance, chemical resistance, mechanical strength and the like. Therefore, they are molded into fibers, films and other articles and used in various fields. However, they have drawbacks such as they cause deterioration and discoloration due to environmental conditions and action of microorganisms. Although, in Japanese Patent Kokai No. 59-211678, Japanese Patent Kokoku Nos. 60-44423, 60-212415 and 61-98706, there is proposed to add an anti-fungus agent or a mildew proofing agent to product during a post-treatment to prevent deterioration and discoloration by microorganisms, these agents are still insufficient from the view points of mildew proofing effect and its durability.